Fluid carbon dioxide composition



Feb. 9, 1954 D. MAPES FLUID CARBON DIOXIDE COMPOSITION Filed Oct. 26,1951 .F 2 y 2 E INVENTOR Mayne/s W4 A TTOR/VE Y Jambl h i v 1 PatentedFeb. 9, 1954 FLUID CARBON DIOXIDE COMPOSITION Daniel Manes, WestCaldwell, N. J., asslgnor to Specialties Development Corporation,Belleville, N. J a corporation of New Jersey Application October 26,1951, Serial No. 253,243

Claims.

The present invention relates to charges of liquid carbon dioxidecapable of being stored and discharged at extremely low temperatures,and, more particularly, relates to improvements over my prior UnitedStates patent, No. 2,521,526, issued September 5, 1950.

The aforementioned patent discloses the provision of charges of carbondioxide confined under pressure in a fluid-tight storage containerhaving a closure controlled discharge passage and adapted to bedischarged from the container at a relatively high rate at temperaturesas low as about -60 F. without a tendency to clog the passage. This isaccomplished by establishing a charge in th container comprisingprincipally carbon dioxide and a compressed gas inert to carbon dioxide,such as nitrogen for example, which i capable of exerting a substantialpressure at low temperatures while confined within the container. Theweight of the charge in relation to the volumetric capacity of thecontainer is such that the charge is safely confineable in the containerwithout building up excessive pressures at temperatures as high as about140 F., and the compressed gas is present in proportion to the carbondioxide to enact with the carbon dioxide to cause the charge to exert onthe container, at

low temperatures, a pressure suflicient to efiect discharge of thecharge.

While the charges provided in the foregoing manner can be dischargedeffectively and re liahiy at about -60 F. and in some instances at about-65 F., extensive tests have indicated that such charges cannot besafely recommended for discharge at temperatures approaching .70 F. andeven lower, which temperatures, due to the development of higheraltitude flying and th extension of arctic operations, are now morefrequently encountered.

Theoretically, liquid carbon dioxide normally would solidify in thecontainer at -69.88 F., its triple point temperature, but, with theaddition of the compressed gas, it may well be that solidification isinhibited to some extent at the triple point temperature. However,carefully conducted tests have indicated that effective discharge of thecarbon dioxide cannot be attained at '70 F. even if the confined chargeexerts a pressure of about 400 pounds per square inch on the container,because such a charge, upon expansion through the closure controlledpassage, has a tendency to solidify and clog the passage.

It has also been established that where intermittent discharge of thiscarbon dioxide charge is a requirement in the operation of the apparatusutilizing the charge, that is, the charge is to be released by severalon and off operations of the closure controlled passage, solidification01 carbon dioxide in the passage becomes even more acute. In fact, ithas been determined that charges which can be released in a continuousstream b a single opening of the closure controlled passage at lowtemperatures, exhibit a tendency to clog the passage when an attempt ismade to release the same by on and 01f operation. Thus, at temperaturesof about -60 F., charges which can be reliably released in a continuousstream cannot be safely recommended for on and oif operation. Attemperatures of about 65 F., a second discharge is seldom attained.

Accordingly, an object of the present invention is to provide a chargeof the character indicated herein which i not subject to the foregoingdifliculties.

Another object is to provide such a charge which can be effectivelyreleased in a continuous or intermittent stream at or below the triplepoint temperature of carbon dioxide without solidifica- 0 which will notexert excessive pressures on the container in which it is confined attemperatures of about F.

Another object is to provide such a charge which is fully operative,reliable and can be safely recommended for use over a wider temperaturerange than has been found possible heretofore.

A further object is to provide such charges in a simple, convenient,practical andeconomical manner.

A still further object is to provide such charges which can be confinedin and discharged from existing types of carbon dioxide storage anddispensing apparatus utilized for extinguishing fires, inflating rescuedevices, operating pneumatically powered mechanisms and many other usesin which carbon dioxide is employed.

Other and further objects of the invention will be obvious upon anunderstanding of the illustrative embodiment about to be described, orWill be indicated in the appended claims, and variou ad-- vantages notreferred to herein will occur to one skilled in the art upon employmentof the invention in practice.

In accordance with the invention, it has been found that the foregoingobjects can be accomplished by providing a charge of fluid mediumconfined under pressure in a fluid-tight storage container having aclosure controlled discharge passage, the charge comprising principallycarbon dioxide; 2, halogenated hydrocarbon having a freezing pointtemperature much lower than 70 F. and having a boiling point temperaturehigher than 70 F. while under a pressure of about 150 pounds per squareinch absolute and having a vapor pressure at 160 F. which is lower thanthat of carbon dioxide at such temperature, the halogenated hydrocarbonbeing in admixture with the carbon dioxide in an amount sufficient tomaintain the carbon dioxide in fluid state at and below its triple pointtemperature while confined in the container; and a compressed gas inertto carbon dioxide and the halogenated hydrocarbon, which gas is capableof exerting a pres- 'sure of at least 100 pounds per square inchabsolute at 80 F. while confined within the container, the weight of thecharge in relation to the volumetric capacity of the container beingsuch that the charge is safely confineable in the container withoutbuilding up excessive pressures at temperatures as high as about 169 F.and the inert gas being present in an amount sufficient to coact withthe carbon dioxide and the halogenated hydrocarbon to cause the chargeto exert on the container a pressure in excess of aboutlOO pounds persquare inch absolute at about 80 F., whereby the charge is continu-'ously and intermittently dischargeable from the container at arelatively high rate at temperatures below 70 F. without a tendency tosolidify and clog the passage through which it is discharged.

In the drawing, the single figure is a fragmentary, longitudinalsectional view of apparatus including a container provided with a valvehaving a closure controlled discharge passage, such apparatus beingadapted for confining and discharging the charges in accordance with thepresent invention.

Referring to the drawing, there is shown a -metallic container in of thetype generally utilized for storing liquid carbon dioxide. The corntainer is constructed in the usual manner, and,

for example, maybe of the type adapted to safely withstand internalpressures of about 3600 pounds per square inch or such other pressuresat which the charge therein is to be confined.

In compliance with existing Interstate Commerce Commission regulations,the weight of the carbon dioxide in a container of such design shall notexceed 68% of the Weight of the water at 4 C. which would completelyfill the container, such 68% filling being known in the art as thenormal filling capacity or the normal volumetric carbon dioxide capacityof the container. While the present invention is adapted to be practicedin connection with containers coming within these regulations, it willbe understood that the invention can likewise be practiced in connectionwith containers not subject to Interstate Commerce Commissionregulations wherein higher filling percentages are permitted; and thatthe description of the present invention in connection with containersfilled to less than their normal capacity is to be taken as illustrativeof the optimum advantages adapted to be attained.

As shown, the upper end of the container is provided with an opening I2in which is secured a suitable valve or discharge fitting IA. The valvehas a discharge passage including an inlet it to which is attached asyphon tube 18 extending to the bottom of the container, and includingan outlet 20 for connecting a hose or the like adapted to conduct thecarbon dioxide to its point of use. Intermediate the inlet and outlet, avalve seat 22 is provided for receiving a valve member 26 adapted tocontrol the flow of the carbon dioxide charge confined in the containerthrough the passage. A manually operable handwheel 28 and a threadedstem 28, adapted to effect unseating and seating of the valve member 24to open and close the passage at will, are shown by way of example.

A safety discharge assembly 30 may be provided intermediate the inlet I6 of the valve and the valve seat 22 for discharging the contents of thecontainer to the atmosphere in the event the pressure within thecontainer exceeds a predetermined safe working pressure, Discharge ofthe contents of the container in this manner is controlled by a disc 32adapted to rupture when the predetermined pressure has been exceeded.

The compressed inert gas (other than carbon dioxide) may be a gas ormixture of gases adapted to exist in gaseous state and adapted to exerta substantial pressure at the low temperatures contemplated herein. Suchgases may be air, argon, carbon monoxide, carbon tetrafiuoride, helium,hydrogen, neon, nitrogen and oxygen. These gases all have a much lowercritical temperature than the triple point temperature of carbondioxide, and, for example, are adapted to exist in compressed gaseousstate and exert at least 100 pounds per square inch absolute whenconfined in the container at a temperature of about F.

For all-around purposes, nitrogen is preferred because of its inertproperties, but compressed air may be used to good advantage because ofits general availability and low cost.

' By the term halogenated hydrocarbons is meant hydrocarbons having oneor more hydrogen atoms substituted by an atom of the halogens, to Wit,bromine, chlorine, fluorine and/or iodine. This term in its broad senseis intended to include ethers of such compounds and halocarbons whereinall of the hydrogen atoms have been substituted by halogen atoms.

contain incompletely halogenated fractions in minor quantities. It isalso contemplated that such halogenated hydrocarbons may be used singlyor in admixture. In the following table,

6 oxide at this temperature and will not: adversely enact the over-allpressure oi the examples of such halogenated hydrocarbons and thepertinent available physical properties thereo! are given. charge atsuch temperature.

Mole- Critical Critical Freezing Boiling No. Compound cular TemperWeight mm Pressure Point Point F. P. a. 2'. F. F.

105 84 540 -296 '112 120 233 582 -2I=2 22 137 388 635 -J 68 210 389 6001l2 76 149 158 635 356 -76 70 730 256 -ll6 86.5 205 716 256 -41 103 353750 2ll 48 85 421 640 -l .3 104 34 I13 892 --238 -1D8 381 760 38 138 76480 109 164 112 4.00 100 -74 171 294 474 -137 38 188 165 353 298 -36 Atatmospheric pressure.

It will be noted that compounds Nos. 1 to 22 all have a freezing pointtemperature lower than the triple point of carbon dioxide and thereforeare adapted to exist in fluid state at about 70 F. Also, these compounds(with the exception of compounds Nos. 1, 5, 6, 10, 12, and 13) have aboiling point temperature higher than the triple point of carbondioxide. However, compounds Nos. 1, 5, 6, 10, 12, and 13 have a boilingpoint temperature higher than -70 F. while confined under a pressure ofabout 150 pounds per square inch, whereby all of these compounds areadapted to exist in liquid state when so confined at a temperature ofabout 70 F. Thus, when these compounds are admixed with carbon dioxideand the mixture is confined in a fluid-tight container at 70 F. orlower, a mutually solvent liquid system is believed to be established.

It will further be noted that compounds Nos. 2 to 11 and 13 to 17 have ahigher critical temperature than that'of carbon dioxide (87.8 F.), andhave a lower critical pressure than that or carbon dioxide (1070 poundsper square inch absolute). Consequently, these compounds at about F.have a lower vapor pressure than that of carbon dioxide at suchtemperature,

whereby the vapor pressure of such compounds will not materiallycontribute to the over-all pressure of the charge at such temperature,and in fact a lower over-all pressure will result where a portion of thecarbon dioxide of the charges illustrated and described in theaforementioned patent is substituted by an amount of such compounds. Inthis ,manner, carbon dioxide and these halogenated hydrocarbons can beutilized together in a charge without building up, at 160 F., pressuresexceeding the safe working pressure of the container, provided of coursethe combined weight of the carbon dioxide and the halogenatedhydrocarbon components of the charge in relation to the volumetriccapacity of the container is within safe limits. j

Compounds Nos. 1 and 12 have a critical temperature slightly lower thanthat of carbon dioxide, but have a critical pressure much lower thanthat or carbon dioxide. These compounds at 160 F. have a lower pressurethan carbon di- The critical temperature and the critical pressure dataof compounds Nos. 19 and 20 could not be located, but, from generalobservations these compounds are believed to be adapted for use inconnection with practicing the invention. Similarly, pertinent data oncompounds Nos. 23 to 27 were not available. However, these compounds areclosely related to either compound No. 5 or compound No. 19, and arebelieved to b suitable.

In practicing the invention, the selection of any particular compound orcompounds listed in the table dependsprimarily on cost and generalavailability in commercial quantities and also on non-flammability andnon-toxicity. Where'tha charge is utilized in the extinguishment of:fires, non-flammability and high stability are desirable, and goodextinguishing characteristics are preferred. Where the charge is to" bereleased into the atmosphere in the vicinity of human beings,non-toxicity is an important factor. The molecular weight of thecompound may also be a factor, in view of the fact that tests haveindicated that in using equal amounts by weight of compounds havingdifierent molecular weights. those compounds having the lower molecularweights appear to be most effective in maintaining the carbon dioxide inliquidstate at temperatures below '70 F.

The amounts of carbon dioxide, inert compressed gas and halogenatedhydrocarbon compound comprising the charge maybe varied considerably butin all cases the carbon dioxide is the principal component of thecharge. Preferably, the combined amounts of the carbon dioxide and thehalogenated hydrocarbon are equivalent to between about 65 and about 140parts by weight, and the amount of nitrogen or other gas is equivalentto between about 3 and 10 parts by weight. Charges comprising suchproportions of components, when confined in containers in amounts toprovide between about 50% and about 95% normal filling thereof, exert apressure of between about at least 100 and about 4001 pounds per squareinch at -70 F. and exert a pressure at 160 F. which does not exceed theworking pressure the container can safely withstand.

The DIOPOI'tIOIITOf carbon dioxide-to halogenated by weight of ahalogenated hydrocarbon com- Example 17' A fifth charge was prepared inthe foregoing manner comprising 3.5 pounds of carbon dioxide, one poundof compound No. 2 of the table, and .2 pound of nitrogen. This chargehad about the same dischargecharacteristics at -70 F. as the charge ofExample I.

Example VI A sixth charge was prepared in the foregoing mannercomprising35 pounds of carbon dioxide,

one pound of compound No. 2 of the table and .2

pound of nitrogen. This charge had about the pound, and 4 to 8 parts byweight of compressed nitrogen or other gas could be readily dischargedat 70- F. and lower.

In preparing the charges, any of the methods disclosed in theaforementioned patent may be utilized, that is, the carbon dioxide, thehalogenated hydrocarbon and the compressed inert gas may be introducedinto the container in any desired order and the carbon dioxide maybeintroduced in either liquid or solid state.

The following examples illustrate the present invention morespecifically.

Example I A charge was prepared in a container having a normal fillingcapacity of about 5 pounds of carbon dioxide and a volume of about 205cubic" inches by first introducing one pound of com pound No. 5 of thetable, next introducing about .2 pound of dry nitrogen gas, and finallyintroducing 3.5 pounds of liquid carbon dioxide. The charge confined inthe container was stored in a low temperature refrigerator for asufiicient time to bring the temperature thereof to about -'70 F. Thecharge was then released by opening the valve completely, and it wasfound that more than 90% of the charge was discharged through an orificeabout .082 inch in diameter in about 28 seconds. Such discharge comparesfavorably with that of 5 pounds of carbon dioxide from a similarcontainer and through a similar orifice at 70 F.

Example II 'A second charge was prepared in the foregoing manner, andwas discharged while at -70 F; .by intermittently opening the valve forabout 3 seconds and closing the valve for 10 seconds. Prac; tically theentire charge was released from the containerby such intermittent valveopening operations, thereby demonstrating that on and off operation ispossible with such charges at about the triple point temperature ofcarbon dioxide.

Example III A third'char'ge was prepared in'the foregoing manner but thetemperature thereof was brought down to about 80 F., and the charge wasreleased as before at this temperature. Continuous discharge ofabout'90'% of the charge required 32 seconds, thereby demonstrating thatcharges can be released at a good rate whileat temperatures below thetriple point temperature of carbon dioxide.

Example IV pound of nitrogen. About 90% of this charge was r such Idischarged at about --70 F. in about 2.7 seconds.

same discharge characteristics at F. as the charge of Example III.

Example VII A seventh charge was prepared in the foregoing mannercomprising 3.5 pounds of carbon dioxide,

.5 pound of compound No. 2 of the table, and .2 pound of nitrogen. At 70F., more than discharge was accomplished by on and off operation of thevalve. 1

Example VIII The tests in accordance with Examples I to VII wererepeated with the weight of the nitrogen adjusted to .15 pound in oneinstance and to .25 pound in another instance. In all cases, more thanabout 90% discharge was effected, but the use of the larger amount ofnitrogen resulted in a slightly higher discharge rate.

A charge consisting of 5 pounds of carbon dioxide and another chargeconsisting of 4 pounds of carbon dioxide and .2 pound of nitrogen wereeach confined in a container identical to that used in connection withthe foregoing examples. At 70 F., both of these charges failed todischarge due to solidification of carbon dioxide in the valvecontrolled passage and/or in the container.

Further tests were made in connection with the charges in accordancewith Examples I to VII to test their fire extinguishing effectiveness;and in every instance itwas found that these charges at 70 F.extinguished standardtub fires at least as efiectively as chargesconsisting of carbon dioxide at 70 F. 'It was also observed that, wherethese charges were directedthrough a carbon dioxide snow forming shieldor horn of the usual construction, the accumulation of electrostaticcharges on the shield or horn was greatly minimized under conditions oflow temperature and low humidity thereby indicating that the ad ditionof the halogenated hydrocarbon compounds has a desirable electrostaticcharge inhibiting effect.

The pressure/temperature characteristics of charges in accordance withExamples I to- 'VIII were determined by connecting a pressure gage tothe outlet of the containers. At about 80 F., the pressure exerted bythe. charges in all cases exceeded pounds per square inch. absolute,and, at about F., the pressure exerted by the charges in all cases didnot exceed 3000 pounds per square inch absolute which pressure is wellwithin the safe working pressure of the container considerin'g'th'at theusual carbon dioxide charges at 68% filling exert a pressure of about3100 pounds per square inch.

From the foregoing description and examples, it will'be seen that thepresent invention provides improved chargescomprising principally carbondioxide which can be discharged continuously and'intermittently at arelatively high 2,ees,419

rate at extremely low temperatures and which do not exert excessivepressures at high temperatures. These charges can be provided in asimple and economical manner, and can be utilized for many usefulpurposes without the need of specially designed apparatus.

It will be understood that the details and examples hereinbefore setforth are illustrative only, and the invention, as broadly described andclaimed, is in no way limited thereby.

I claim:

1. A charge of fluid medium confined under pressure in a fluid-tightstorage container having a closure controlled discharge passage, saidcharge comprising principally carbon dioxide; a halogenated hydrocarbonhaving a freezing point temperature much lower than -70 F. and hav ing aboiling point temperature higher than 70 F. while under a pressure ofabout 150 pounds per square inch absolute and having a vapor pressure at160 F. which is lower than that of carbon dioxide at such temperature,said halogenated hydrocarbon being in admixture with said carbon dioxidein an amount sufficient to maintain said carbon dioxide in fluid stateat and below its triple point temperature while confined in thecontainer; and a compressed gas inert to carbon dioxide and saidhalogenated hydrocarbon which gas when present in sufficient quantity iscapable of exerting a pressure of at least 100 pounds per square inchabsolute at -80 F. while confined within the container, the weight ofthe charge in relation to the volumetric capacity of the container beingsuch that the charge is safely conflneable in the container withoutbuilding up excessive pressures at temperatures as high as about 160 F.and said inert gas being present in an amount sufiicient to coact withthe carbon dioxide and. said halogenated hydrocarbon to cause the chargeto exert on the container a pressure in excess of about 100 pounds persquare inch absolute at about 80 whereby the charge is dis chargeablefrom the container at a. relatively high rate at temperatures below -70F. without a tendency of the carbon dioxide to solidify and clog thepassage through which it is discharged.

2. A charge according to claim 1 which is equivalent to between about50% and about 95% of the normal carbon dioxide filling capacity of thecontainer.

3. A charge accordin to claim 2 which comprises between about 65 andabout 140 parts by weight of carbon dioxide and said halogenatedhydrocarbon combined, and between about 3 and parts by weight of saidinert gas.

4. A charge according to claim 3 which comprises between about two andabout eight parts by weight of carbon dioxide to one part by weight ofsaid halogenated hydrocarbon.

5. A charge according to claim 1, wherein said halogenated hydrocarbonis substantially nontoxic and non-flammable 6. A charge according toclaim 1, wherein the closure controlled passage includes a valveconstructed and arranged for on and of!" operation and said charge ischaracterized in that it can be released by intermittent operation ofthe valve without solidifying and clogging the passage.

7. A charge according to claim 1 which consists essentially of about 35parts by weightof carbon dioxide, about 10 parts by weight of CE-hBr,and about 2 parts by weight of nitrogen.

8. A charge according to claim 1 which consistsessentially of about 35parts by weight of carbon dioxide, about 5 to 10 parts by weight ofCC12F2, and about 2 parts by weight of nitrogen.

9. A charge according to claim 1 which consists essentially of about 35parts by weight of carbon dioxide, about 5 to 10 parts by weight ofCHzClBr, and about 2 parts by weight of nitrogen.

10. A charge of fluid medium confined under pressure in a fluid-tightstorage container having a closure controlled discharge passage, saidcharge comprising principally carbon dioxide; a halogenated hydrocarbonhaving a freezing point temperature much lower than F. and having aboiling point temperature higher than 70 F. while under a pressure ofabout 150 pounds per square inch absolute, said halogenated hydrocarbonbeing in admixture with said carbon dioxide in an amount suflicient tomaintain said carnon dioxide in fluid state at and below its triplepoint temperature while confined in the container; and a compressed gasinert to carbon dioxide and said halogenated hydrocarbon which gas whenpresent in suflicient quantity is capable of exerting a pressure of atleast 100 pounds per square inch absolute at F. while confined withinthe container, the weight of the charge in relation to the volumetriccapacity of the container being such that the charge is safelyconfincable in the container without building up excessive pressures attemperatures as high as about 160 F. and said inert gas being present inan amount sufficient to coact with the carbon dioxide and saidhalogenated hydrocarbon to cause the charge to exert on the container apressure in excess of about pounds per square inch absolute at about 80F., whereby the charge is dischargeable from the container at arelatively high rate at temperatures below 70 F. without a tendency ofthe carbon dioxide to solidify and clog the passage through which it isdischarged.

DANIEL MAPES.

References Cited in the file of this patent UNITED STATES PATENTS Number

